Pub Date : 2026-01-29DOI: 10.1016/j.oceaneng.2026.124403
Tianze Lu, Cong Wang, Deping Cao
This study presents a parametric SPH investigation into resonant sloshing-structure interaction in rectangular tanks, focusing on coupled effects of water depth and baffle configuration on hydrodynamic loads. A systematic simulation matrix was executed, encompassing variations in baffle quantity, relative height, and filling depth under first-mode resonance excitation. The results reveal two distinct hydrodynamic regimes governed by the relative submergence ratio. For emergent baffles, compartmentalizing the tank effectively suppresses sloshing, drastically reduces wall impact pressures, and yields a monotonic force reduction with increasing baffle count. In contrast, deeply submerged baffles induce a vortex-dominated regime with a non-uniform load distribution. Within this regime, a critical transition occurs at a specific baffle count, leading to a localized force increase on the central baffle due to concentrated vortex shedding. Furthermore, a critical filling depth generating peak wall pressures was identified for unbaffled tanks, which shifts with baffle installation. The study establishes that the relative submergence ratio, in conjunction with the baffle count, governs the sloshing suppression efficiency and baffle load dynamics. Specifically, the baffle count dictates the spatial distribution of hydrodynamic loads, while the relative submergence ratio determines the fundamental operating regime, characterized as either confinement-dominated or vortex-dominated, that defines the system's response.
{"title":"Parametric SPH study on resonant sloshing-structure interaction: coupled effects of water depth and baffle configuration on hydrodynamic loads in rectangular tanks","authors":"Tianze Lu, Cong Wang, Deping Cao","doi":"10.1016/j.oceaneng.2026.124403","DOIUrl":"10.1016/j.oceaneng.2026.124403","url":null,"abstract":"<div><div>This study presents a parametric SPH investigation into resonant sloshing-structure interaction in rectangular tanks, focusing on coupled effects of water depth and baffle configuration on hydrodynamic loads. A systematic simulation matrix was executed, encompassing variations in baffle quantity, relative height, and filling depth under first-mode resonance excitation. The results reveal two distinct hydrodynamic regimes governed by the relative submergence ratio. For emergent baffles, compartmentalizing the tank effectively suppresses sloshing, drastically reduces wall impact pressures, and yields a monotonic force reduction with increasing baffle count. In contrast, deeply submerged baffles induce a vortex-dominated regime with a non-uniform load distribution. Within this regime, a critical transition occurs at a specific baffle count, leading to a localized force increase on the central baffle due to concentrated vortex shedding. Furthermore, a critical filling depth generating peak wall pressures was identified for unbaffled tanks, which shifts with baffle installation. The study establishes that the relative submergence ratio, in conjunction with the baffle count, governs the sloshing suppression efficiency and baffle load dynamics. Specifically, the baffle count dictates the spatial distribution of hydrodynamic loads, while the relative submergence ratio determines the fundamental operating regime, characterized as either confinement-dominated or vortex-dominated, that defines the system's response.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"351 ","pages":"Article 124403"},"PeriodicalIF":5.5,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-29DOI: 10.1016/j.oceaneng.2026.124452
Xiaoyu Bai , Haoran Ma , Yingjie Zhang , Junwei Liu , Zekun Wu , Nan Yan
Coastal underground engineering faces increasing challenges from groundwater buoyancy and corrosive environments. To investigate the bearing performance and load transfer mechanism of Glass Fiber Reinforced Polymer bar micro uplift pile (GFRP-MUP), field pull-out test of GFRP-MUP was conducted in this study. Based on the field test, numerical simulations were also employed to reveal the damaged evolution characteristics of the anchorage body. Field test results show that the bearing capacity of GFRP-MUP increases significantly, approximately 1.7 times that of a Steel-Bar micro uplift pile (SB-MUP) of the same specification, meeting the requirements for pull-out bearing capacity. Under ultimate load, the axial force of GFRP-MUP can be transferred to a depth of up to 3.0 m, and the shear stress at the rod-mortar interface reaches 5.06 MPa, indicating effective bonding performance. Numerical simulations further show that damage in the GFRP-MUP anchorage body ceases at a depth of approximately 2.5 m, the critical anchorage length for GFRP-MUP is approximately 3.5 m. Compared with conventional SB-MUP, it is recommended to use anchorage bodies with larger diameter and shorter length to control the overall displacement of GFRP-MUP and reduce material waste.
{"title":"Bearing behavior and damage mechanisms of GFRP micro uplift piles in coastal areas: Field tests and numerical simulations","authors":"Xiaoyu Bai , Haoran Ma , Yingjie Zhang , Junwei Liu , Zekun Wu , Nan Yan","doi":"10.1016/j.oceaneng.2026.124452","DOIUrl":"10.1016/j.oceaneng.2026.124452","url":null,"abstract":"<div><div>Coastal underground engineering faces increasing challenges from groundwater buoyancy and corrosive environments. To investigate the bearing performance and load transfer mechanism of Glass Fiber Reinforced Polymer bar micro uplift pile (GFRP-MUP), field pull-out test of GFRP-MUP was conducted in this study. Based on the field test, numerical simulations were also employed to reveal the damaged evolution characteristics of the anchorage body. Field test results show that the bearing capacity of GFRP-MUP increases significantly, approximately 1.7 times that of a Steel-Bar micro uplift pile (SB-MUP) of the same specification, meeting the requirements for pull-out bearing capacity. Under ultimate load, the axial force of GFRP-MUP can be transferred to a depth of up to 3.0 m, and the shear stress at the rod-mortar interface reaches 5.06 MPa, indicating effective bonding performance. Numerical simulations further show that damage in the GFRP-MUP anchorage body ceases at a depth of approximately 2.5 m, the critical anchorage length for GFRP-MUP is approximately 3.5 m. Compared with conventional SB-MUP, it is recommended to use anchorage bodies with larger diameter and shorter length to control the overall displacement of GFRP-MUP and reduce material waste.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"351 ","pages":"Article 124452"},"PeriodicalIF":5.5,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-29DOI: 10.1016/j.oceaneng.2026.124355
Bo Jiang , Wei Wang , Binfeng Mao , Shengren Wei , Jiuyang Cang , Zhifan Zhang , Guiyong Zhang
This study investigates the energy-saving and resistance-reduction potential of high-speed catamaran formations, as well as their hydrodynamic performance. It elucidates the hydrodynamic interaction mechanisms between catamarans due to the unique wake field created by the separation of the leading catamaran. Initially, grid convergence analysis was conducted to validate the grid discretization method, followed by numerical-experimental comparisons to verify the accuracy of the numerical approach. A hydrodynamic performance prediction model was developed for three-catamaran formations (irregular tandem, general triangle, and right-angled triangle), to examine the effects of formation layout on resistance and motion responses of both the formation and individual catamarans. The influence of layout asymmetry on fluid dynamic accumulation, wave interference, and phase matching was quantified. The results indicate that within the longitudinal spacing range of ST = 0.75L–1.25L, wave interference leads to destructive wave cancellation, resulting in a maximum resistance reduction of up to 31.8 %, with the tandem formation showing the most favorable performance. Additionally, changes in the catamaran's attitude significantly impact drag variations. These findings provide a basis for fully leveraging the unique configuration and formation advantages of catamarans.
{"title":"Wave interference characteristics of high-speed catamaran formations under various configurations","authors":"Bo Jiang , Wei Wang , Binfeng Mao , Shengren Wei , Jiuyang Cang , Zhifan Zhang , Guiyong Zhang","doi":"10.1016/j.oceaneng.2026.124355","DOIUrl":"10.1016/j.oceaneng.2026.124355","url":null,"abstract":"<div><div>This study investigates the energy-saving and resistance-reduction potential of high-speed catamaran formations, as well as their hydrodynamic performance. It elucidates the hydrodynamic interaction mechanisms between catamarans due to the unique wake field created by the separation of the leading catamaran. Initially, grid convergence analysis was conducted to validate the grid discretization method, followed by numerical-experimental comparisons to verify the accuracy of the numerical approach. A hydrodynamic performance prediction model was developed for three-catamaran formations (irregular tandem, general triangle, and right-angled triangle), to examine the effects of formation layout on resistance and motion responses of both the formation and individual catamarans. The influence of layout asymmetry on fluid dynamic accumulation, wave interference, and phase matching was quantified. The results indicate that within the longitudinal spacing range of <em>ST</em> = 0.75<em>L</em>–1.25<em>L</em>, wave interference leads to destructive wave cancellation, resulting in a maximum resistance reduction of up to 31.8 %, with the tandem formation showing the most favorable performance. Additionally, changes in the catamaran's attitude significantly impact drag variations. These findings provide a basis for fully leveraging the unique configuration and formation advantages of catamarans.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"351 ","pages":"Article 124355"},"PeriodicalIF":5.5,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-29DOI: 10.1016/j.oceaneng.2026.124287
Chenguang Bai, Jianing Zhang, Zekun Peng, Changzhi Zhao, Lei Zhang
This study investigates bidirectional coupling between hull motions and tank sloshing in the 90 m flow-through aquaculture vessel “Minde”. Using a Computational Fluid Dynamics (CFD) approach validated by model experiments, this study analyzes coupled heave and pitch as well as internal sloshing. Side openings reduce displacement and moments of inertia and thus attenuate pitch and heave. With increasing wavelength, pitch increases, heave peaks at mid wavelength, and the dominant sloshing frequency decreases. The first tank, farther from the center of gravity, is pitch dominated with larger free surface amplitudes and faster response, while the second is heave dominated and develops higher bulkhead pressures. Vortices form near the side shell openings, move toward the tank center, re-enter with flow direction change, and accelerate the inflow. Increasing wave height amplifies vessel motions and tank sloshing. In the first tank, side shell pressure shows a double-peak and decreases with wave height, whereas transverse bulkhead pressure increases.Inflow velocity rises with wave height and is higher in the first tank. This study systematically reveals the bidirectional coupling mechanism of flow-through aquaculture vessels under different wave parameters.
{"title":"Bidirectionally coupled sloshing of a flow-through aquaculture vessel with side openings in waves","authors":"Chenguang Bai, Jianing Zhang, Zekun Peng, Changzhi Zhao, Lei Zhang","doi":"10.1016/j.oceaneng.2026.124287","DOIUrl":"10.1016/j.oceaneng.2026.124287","url":null,"abstract":"<div><div>This study investigates bidirectional coupling between hull motions and tank sloshing in the 90 m flow-through aquaculture vessel “Minde”. Using a Computational Fluid Dynamics (CFD) approach validated by model experiments, this study analyzes coupled heave and pitch as well as internal sloshing. Side openings reduce displacement and moments of inertia and thus attenuate pitch and heave. With increasing wavelength, pitch increases, heave peaks at mid wavelength, and the dominant sloshing frequency decreases. The first tank, farther from the center of gravity, is pitch dominated with larger free surface amplitudes and faster response, while the second is heave dominated and develops higher bulkhead pressures. Vortices form near the side shell openings, move toward the tank center, re-enter with flow direction change, and accelerate the inflow. Increasing wave height amplifies vessel motions and tank sloshing. In the first tank, side shell pressure shows a double-peak and decreases with wave height, whereas transverse bulkhead pressure increases.Inflow velocity rises with wave height and is higher in the first tank. This study systematically reveals the bidirectional coupling mechanism of flow-through aquaculture vessels under different wave parameters.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"351 ","pages":"Article 124287"},"PeriodicalIF":5.5,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-29DOI: 10.1016/j.oceaneng.2026.124371
Shengjie Rui , Hans Petter Jostad , Lizhong Wang , Xi Chen , Zefeng Zhou
Soft soil deformation and erosion induced by riser motion strongly influence seabed trench development near the touchdown zone, with consequences for pipeline fatigue damage. Although previous studies highlight the influence of riser motion and clay softening, the detailed trenching mechanisms remain insufficiently understood. To address these gaps, this study directly visualizes trench development using camera-based monitoring, identifies the sequential mechanisms of trench formation, and reveals the critical contribution of soil cutting beneath a moving riser. In this paper, a series of T-bar penetration tests were conducted to investigate clay deformation and erosion representative of the riser touchdown zone. Undrained shear strength, cyclic amplitude and initial position were varied, and deformation and erosion were recorded in real time. The potential mechanisms of trench formation arising from pipeline–seabed interaction were then synthesised. Results indicate four deformation regimes, classified by penetration depth and motion amplitude, progressing from negligible flowback at shallow penetration to pronounced flowback, cutting and adhesion as depth increases, each strongly affecting erosion. Clay erosion occurs through two primary mechanisms: water-replacement erosion and moving-structure erosion. In the former, high local velocities generated as the T-bar approaches the clay surface entrain fines and strip surficial material, whereas in the latter, cutting produces adherent clay that is subsequently ablated by relative water–structure motion.
{"title":"Soft soil deformation and erosion in riser touchdown zone: insights from T-bar penetration tests","authors":"Shengjie Rui , Hans Petter Jostad , Lizhong Wang , Xi Chen , Zefeng Zhou","doi":"10.1016/j.oceaneng.2026.124371","DOIUrl":"10.1016/j.oceaneng.2026.124371","url":null,"abstract":"<div><div>Soft soil deformation and erosion induced by riser motion strongly influence seabed trench development near the touchdown zone, with consequences for pipeline fatigue damage. Although previous studies highlight the influence of riser motion and clay softening, the detailed trenching mechanisms remain insufficiently understood. To address these gaps, this study directly visualizes trench development using camera-based monitoring, identifies the sequential mechanisms of trench formation, and reveals the critical contribution of soil cutting beneath a moving riser. In this paper, a series of T-bar penetration tests were conducted to investigate clay deformation and erosion representative of the riser touchdown zone. Undrained shear strength, cyclic amplitude and initial position were varied, and deformation and erosion were recorded in real time. The potential mechanisms of trench formation arising from pipeline–seabed interaction were then synthesised. Results indicate four deformation regimes, classified by penetration depth and motion amplitude, progressing from negligible flowback at shallow penetration to pronounced flowback, cutting and adhesion as depth increases, each strongly affecting erosion. Clay erosion occurs through two primary mechanisms: water-replacement erosion and moving-structure erosion. In the former, high local velocities generated as the T-bar approaches the clay surface entrain fines and strip surficial material, whereas in the latter, cutting produces adherent clay that is subsequently ablated by relative water–structure motion.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"351 ","pages":"Article 124371"},"PeriodicalIF":5.5,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-29DOI: 10.1016/j.oceaneng.2026.124345
Burcu Ozselek, Erinc Dobrucali, Yunus Onur Yildiz
Dry docking operations play a critical role in shipyards, where timely repairs are essential due to high freight rates. Therefore, the efficient utilization and capacity enhancement of dry docks are vital for maximizing operational productivity and economic returns. This study examines the structural feasibility and operational benefits of incorporating a modular steel separator into a dry dock to accommodate multiple vessels simultaneously. Finite Element Method (FEM) analysis was conducted using ANSYS Workbench to evaluate the mechanical behavior of four steel beam cross-sections under hydrostatic pressure. Among the tested profiles, the rectangular tube demonstrated the most efficient load-bearing performance, with acceptable stress and deformation values across all cases. Beyond structural integrity, the separator offers notable gains in operational efficiency. Energy saving is changing between 25 % and 60 % per year from the discharging process when graving docks can service multiple vessels simultaneously. Economic analysis demonstrates that under conservative assumptions (5 % capacity increase), the system achieves payback within 5 years, while moderate utilization scenarios (50 % capacity increase) yield payback in approximately 6 months. These findings provide a foundational basis for future studies involving 3D modeling of separator and real implementation of modular dry dock systems in shipyards.
{"title":"Structural analysis and operational implications of a dry dock separator","authors":"Burcu Ozselek, Erinc Dobrucali, Yunus Onur Yildiz","doi":"10.1016/j.oceaneng.2026.124345","DOIUrl":"10.1016/j.oceaneng.2026.124345","url":null,"abstract":"<div><div>Dry docking operations play a critical role in shipyards, where timely repairs are essential due to high freight rates. Therefore, the efficient utilization and capacity enhancement of dry docks are vital for maximizing operational productivity and economic returns. This study examines the structural feasibility and operational benefits of incorporating a modular steel separator into a dry dock to accommodate multiple vessels simultaneously. Finite Element Method (FEM) analysis was conducted using ANSYS Workbench to evaluate the mechanical behavior of four steel beam cross-sections under hydrostatic pressure. Among the tested profiles, the rectangular tube demonstrated the most efficient load-bearing performance, with acceptable stress and deformation values across all cases. Beyond structural integrity, the separator offers notable gains in operational efficiency. Energy saving is changing between 25 % and 60 % per year from the discharging process when graving docks can service multiple vessels simultaneously. Economic analysis demonstrates that under conservative assumptions (5 % capacity increase), the system achieves payback within 5 years, while moderate utilization scenarios (50 % capacity increase) yield payback in approximately 6 months. These findings provide a foundational basis for future studies involving 3D modeling of separator and real implementation of modular dry dock systems in shipyards.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"351 ","pages":"Article 124345"},"PeriodicalIF":5.5,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080464","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-29DOI: 10.1016/j.oceaneng.2026.124418
Hao Jin , Liming Wang , Wang Gao , Fanghong Huang , Yang Wang
Traditional surface spalling detection for underwater concrete structures, which typically relies on manual surveying or optical visualization, is inefficient, dangerous, and susceptible to environmental influences. While deep learning-based sonar image segmentation methods, as an alternative, have been explored, the low contrast and complex background of sonar images typically bring about spatial redundancy, limiting segmentation performance. With the purpose of addressing this issue, a spatial redundancy auxiliary loss function (SRA Loss) combined with a dynamic loss training strategy (DLTS) is proposed in this study to suppress redundant feature representations and enhance feature diversity. Experiments on the independently constructed SonarS560 dataset demonstrate that this method effectively improves segmentation accuracy, guiding automated inspection and intelligent maintenance of underwater concrete structures in ocean engineering.
{"title":"Surface spalling segmentation algorithm of underwater concrete structures based on sonar images: Auxiliary loss and dynamic training","authors":"Hao Jin , Liming Wang , Wang Gao , Fanghong Huang , Yang Wang","doi":"10.1016/j.oceaneng.2026.124418","DOIUrl":"10.1016/j.oceaneng.2026.124418","url":null,"abstract":"<div><div>Traditional surface spalling detection for underwater concrete structures, which typically relies on manual surveying or optical visualization, is inefficient, dangerous, and susceptible to environmental influences. While deep learning-based sonar image segmentation methods, as an alternative, have been explored, the low contrast and complex background of sonar images typically bring about spatial redundancy, limiting segmentation performance. With the purpose of addressing this issue, a spatial redundancy auxiliary loss function (SRA Loss) combined with a dynamic loss training strategy (DLTS) is proposed in this study to suppress redundant feature representations and enhance feature diversity. Experiments on the independently constructed SonarS560 dataset demonstrate that this method effectively improves segmentation accuracy, guiding automated inspection and intelligent maintenance of underwater concrete structures in ocean engineering.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"351 ","pages":"Article 124418"},"PeriodicalIF":5.5,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-29DOI: 10.1016/j.oceaneng.2026.124422
Zihan Liu , Zhiyu Jiang , Lorenzo Cappietti
The wave attenuation performance of floating breakwaters (FBs) is usually limited under long wave conditions. This study investigated wing-type FBs in a two-dimensional wave flume, using the Smoothed Particle Hydrodynamics (SPH) method, which was validated against previous experiments. To minimise the cross-sectional area (Area) while ensuring effective wave attenuation (with transmission coefficient kt < 0.20) of a wing-type FB, the geometric parameters, including FB width (WFB) and draft (DFB), as well as wing height (Hwing), width (Wwing), and angle (Awing), were optimised under the selected extreme wave condition. A Support Vector Regression (SVR)-trained surrogate model was used to predict kt for wing-type FBs, and a genetic algorithm (GA) was applied to identify the optimal solutions. The effects of geometric parameters and wave conditions on the hydrodynamic responses of wing-type FBs were analysed. The results showed that, compared with the initially designed wing-type FB, the optimal solution reduced the Area by 20 %, increased WFB by 15 %, and decreased DFB by 47 %. As Awing and Hwing/Lw (Lw is wavelength) increased, kt decreased and then increased, with the minimum values occurring when Awing was between 20° and 40° and Hwing/Lw was between 0.02 and 0.03. Increasing Wwing, DFB, or WFB reduced kt. For incident wave periods T ≥ 0.9 s, the optimised wing-type FB showed improved wave attenuation compared with the box-type FB; for T < 1.1 s, kt of the wing-type FB was less than 0.60. This study offers a useful reference for the design of FBs in offshore environments.
{"title":"Hydrodynamics-based geometric optimisation and parametric analysis of a wing-type floating breakwater","authors":"Zihan Liu , Zhiyu Jiang , Lorenzo Cappietti","doi":"10.1016/j.oceaneng.2026.124422","DOIUrl":"10.1016/j.oceaneng.2026.124422","url":null,"abstract":"<div><div>The wave attenuation performance of floating breakwaters (FBs) is usually limited under long wave conditions. This study investigated wing-type FBs in a two-dimensional wave flume, using the Smoothed Particle Hydrodynamics (SPH) method, which was validated against previous experiments. To minimise the cross-sectional area (<em>Area</em>) while ensuring effective wave attenuation (with transmission coefficient <em>k</em><sub><em>t</em></sub> < 0.20) of a wing-type FB, the geometric parameters, including FB width (<em>W</em><sub><em>FB</em></sub>) and draft (<em>D</em><sub><em>FB</em></sub>), as well as wing height (<em>H</em><sub><em>wing</em></sub>), width (<em>W</em><sub><em>wing</em></sub>), and angle (<em>A</em><sub><em>wing</em></sub>), were optimised under the selected extreme wave condition. A Support Vector Regression (SVR)-trained surrogate model was used to predict <em>k</em><sub><em>t</em></sub> for wing-type FBs, and a genetic algorithm (GA) was applied to identify the optimal solutions. The effects of geometric parameters and wave conditions on the hydrodynamic responses of wing-type FBs were analysed. The results showed that, compared with the initially designed wing-type FB, the optimal solution reduced the <em>Area</em> by 20 %, increased <em>W</em><sub><em>FB</em></sub> by 15 %, and decreased <em>D</em><sub><em>FB</em></sub> by 47 %. As <em>A</em><sub><em>wing</em></sub> and <em>H</em><sub><em>wing</em></sub>/<em>L</em><sub><em>w</em></sub> (<em>L</em><sub><em>w</em></sub> is wavelength) increased, <em>k</em><sub><em>t</em></sub> decreased and then increased, with the minimum values occurring when <em>A</em><sub><em>wing</em></sub> was between 20° and 40° and <em>H</em><sub><em>wing</em></sub>/<em>L</em><sub><em>w</em></sub> was between 0.02 and 0.03. Increasing <em>W</em><sub><em>wing</em></sub>, <em>D</em><sub><em>FB,</em></sub> or <em>W</em><sub><em>FB</em></sub> reduced <em>k</em><sub><em>t</em></sub>. For incident wave periods <em>T</em> ≥ 0.9 s, the optimised wing-type FB showed improved wave attenuation compared with the box-type FB; for <em>T</em> < 1.1 s, <em>k</em><sub><em>t</em></sub> of the wing-type FB was less than 0.60. This study offers a useful reference for the design of FBs in offshore environments.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"351 ","pages":"Article 124422"},"PeriodicalIF":5.5,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-29DOI: 10.1016/j.oceaneng.2026.124367
Hanqi Zeng , Hao Chen , Junwei Ye , Deping Cao
Oscillating submerged horizontal plate breakwaters (OSHPBs) offer enhanced wave attenuation compared to fixed structures, yet their analysis remains computationally intensive. This study addresses this limitation by developing a novel analytical framework that extends classical wave–fixed plate theory to incorporate prescribed oscillatory motion. Using matched eigenfunction expansion, an efficient analytical solution is derived to resolve wave-plate coupling. Validation is performed with a high-fidelity OpenFOAM model, showing excellent agreement while circumventing experimental challenges. A key advance is the establishment of an empirical relation linking geometric porosity to an equivalent porous parameter, thereby improving physical fidelity. To systematically evaluate accuracy across a high-dimensional parameter space, a Random Forest model is trained on 235 numerical cases and assessed via Mean Absolute Percentage Deviation (MAPD). Results indicate that dimensionless wave parameters (kdd0 or kh) and amplitude-to-depth ratio (Ap/d0) dominate error, with MAPD < 20 % achieved when kdd0 < 1.8 or kh < 3.4, and Ap/d0 < 0.15. Within this validated range, the analytical solution provides a computationally efficient, physically informed tool for OSHPB design.
{"title":"An analytical solution and its data-driven applicability domain for oscillating submerged horizontal plate breakwaters","authors":"Hanqi Zeng , Hao Chen , Junwei Ye , Deping Cao","doi":"10.1016/j.oceaneng.2026.124367","DOIUrl":"10.1016/j.oceaneng.2026.124367","url":null,"abstract":"<div><div>Oscillating submerged horizontal plate breakwaters (OSHPBs) offer enhanced wave attenuation compared to fixed structures, yet their analysis remains computationally intensive. This study addresses this limitation by developing a novel analytical framework that extends classical wave–fixed plate theory to incorporate prescribed oscillatory motion. Using matched eigenfunction expansion, an efficient analytical solution is derived to resolve wave-plate coupling. Validation is performed with a high-fidelity OpenFOAM model, showing excellent agreement while circumventing experimental challenges. A key advance is the establishment of an empirical relation linking geometric porosity to an equivalent porous parameter, thereby improving physical fidelity. To systematically evaluate accuracy across a high-dimensional parameter space, a Random Forest model is trained on 235 numerical cases and assessed via Mean Absolute Percentage Deviation (<em>MAPD</em>). Results indicate that dimensionless wave parameters (<em>k</em><sub><em>d</em></sub><em>d</em><sub>0</sub> or <em>kh</em>) and amplitude-to-depth ratio (<em>A</em><sub><em>p</em></sub>/<em>d</em><sub>0</sub>) dominate error, with <em>MAPD</em> < 20 % achieved when <em>k</em><sub><em>d</em></sub><em>d</em><sub>0</sub> < 1.8 or <em>kh</em> < 3.4, and <em>A</em><sub><em>p</em></sub>/<em>d</em><sub>0</sub> < 0.15. Within this validated range, the analytical solution provides a computationally efficient, physically informed tool for OSHPB design.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"351 ","pages":"Article 124367"},"PeriodicalIF":5.5,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-28DOI: 10.1016/j.oceaneng.2026.124305
Haoruo Chai , Tiedong Zhang , Xun Yan
This study presents an extended Kalman filter (EKF)-based adaptive integral model predictive control (MPC) strategy for the depth regulation of an autonomous underwater vehicle (AUV) equipped with a moving mass control (MMC) system. The EKF is employed to enable real-time estimation of uncertain system parameters under measurement noise, thereby ensuring continuous online model adaptation. To compensate for steady-state errors caused by the angle of attack, an integral action is explicitly embedded within the MPC framework, which allows for systematic tuning of the integral gain as well as the incorporation of anti-windup strategies. Furthermore, a novel adaptive anti-windup mechanism is proposed to suppress excessive integral accumulation while preserving continuous integral dynamics, thereby improving control smoothness and robustness in the presence of actuator saturation and hysteresis. The closed-loop stability of the proposed controller is rigorously analyzed and theoretically guaranteed. Comprehensive simulation and experimental results demonstrate the effectiveness of the proposed approach.
{"title":"EKF-based adaptive integral MPC for depth control of an AUV under uncertainties and constraints","authors":"Haoruo Chai , Tiedong Zhang , Xun Yan","doi":"10.1016/j.oceaneng.2026.124305","DOIUrl":"10.1016/j.oceaneng.2026.124305","url":null,"abstract":"<div><div>This study presents an extended Kalman filter (EKF)-based adaptive integral model predictive control (MPC) strategy for the depth regulation of an autonomous underwater vehicle (AUV) equipped with a moving mass control (MMC) system. The EKF is employed to enable real-time estimation of uncertain system parameters under measurement noise, thereby ensuring continuous online model adaptation. To compensate for steady-state errors caused by the angle of attack, an integral action is explicitly embedded within the MPC framework, which allows for systematic tuning of the integral gain as well as the incorporation of anti-windup strategies. Furthermore, a novel adaptive anti-windup mechanism is proposed to suppress excessive integral accumulation while preserving continuous integral dynamics, thereby improving control smoothness and robustness in the presence of actuator saturation and hysteresis. The closed-loop stability of the proposed controller is rigorously analyzed and theoretically guaranteed. Comprehensive simulation and experimental results demonstrate the effectiveness of the proposed approach.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"351 ","pages":"Article 124305"},"PeriodicalIF":5.5,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}